IL-17F (also known as ML-1) is a member of the IL-17 family of cytokines, which also includes the proteins IL-17A (also known as CTL-8, IL-17), IL-17B, IL-17C, IL-17D, IL-17E (also called IL-25). Both IL-17A and IL-17F are secreted as disulfide linked homodimers which signal through the receptors IL-17R, IL-17RC, or a multimeric receptor complex composed of the IL-17R and IL-17RC. Both are also co-expressed on the same T cell subsets (principally by the Th17 CD4+ T cells). IL-17A and IL-17F also interact and form a heterodimeric IL-17A/IL-17F complex.
Elevated levels of IL-17F and the IL-17A/IL-17F complex have been associated with a variety of inflammatory disorders and autoimmune diseases. Accordingly, there exists a need for therapies that neutralize the biological activities of IL-17F.